Find all integer solutions (Russian Math Olympiad)

Similar matrices have the same characteristic polynomial

a * b = ab + a + b

Prove that (1/x + 1/y + 1/z) is greater than 3

Estonian Math Olympiad

Kaprekar's Constant

Find the smallest n

n! = 8 + 2^k

A Canadian Problem

Prove that n^3 +11n is divisible by 6

x^y = y^(x-y)

Integrate x^-x dx

2^(2^x) = 16^(16^16)

x^2 + cos x = 2024

(n-1)!+1 = n^2

1995 British Mathematics Olympiad problem

Find a+b+c+d

A peek into some geometry

2010 applications of f

Find the sum of all possible values of x² + y²

Find log_x (y)

A beautiful integral for the mind

Find (x+y+z) [Harvard-MIT] Guts contest

Graphs don't intersect? k must be ...........

Find all integer solutions (Russian Math Olympiad)